Drop leg support for trailers



Pll 24, 1945 R. M. BARNHART ET ALv 2,374,320

DROP LEG SUPPORT FOR TRAILERS Filed Nov. e, 1942 3 Sheets-sheet 1 pril 24, 1945. R. M. BARNHART ETAL 2,374,320

DROP LEG SUPPORT FOR TRAILERS Filed Nov. 6, 1942 3 Sheets-Sheet 2 April 24 1945 R. M. BARNHART ET AL 2 374 320 DROP LEG SUPPORT FOR TRAILERS Filed Nov. .6, 1942 5 Sheets Sh t Parc/val M. Hamm/Mdr .farlzeys Patented Apr. 24, 1945 l DROP LEG SUPPORT FOR TRAILERS Robert M. Barnhart, San Gabriel, John C. Bennett, Pasadena, and Percival M. Heinmiller, Los Angeles, Calif., assignors to Utility Trailer Manufacturing Company, Los Angeles, Calif., a corporation of California Application November s, 1942, serial No. 464,777

15 Claims.

This invention has to do with supports for semi-trailers, and its general purpose is the provision of a trailer support of the drop leg type of improved form, simplicity and reliability. Other objects and corresponding accomplishments of the invention will be understood from the following description of typical forms of the invention; but among those objects and accomplishments we may mention preliminarily the locking of the support in its lowered operative position, and in an adjusted lowered position.

In the operation of the support in accordance with this invention, the movement of lowering the support is followed by a final locking movement which locks the support in its lowered operative position. And that lnal locking movement, which locks the support effectively in its lowered trailer-supporting position,l is utilized for the purpose of unlocking the coupler which connects the semi-trailer with the tractor or other towing vehicle. The operation is such that the coupler cannot be unlocked until the support is either nally locked or is finally put into a potential condition in which imposition of the trailer weight must cause iinal locking of the support. All of this results in maximum dependability,-not only of the support, but of the whole interlocked system which includes the support and the coupler. Y 5

The improved type of support and its lookin action may be cooperated with different types of couplers and coupler locking mechanisms. The one which we show and describehereis not, in and of itself, a part of the presentinvention, except insofar as it acts broadly invcombination with the operation of support locking as herein- `after described. The coupler and its locking mechanism is the subject of a copending application Ser. No. 464.776, filed November 6, 1942, now Patent No. 2,355,775,.dated August 15, 1944; and its showing in this application may be take as typical of such couplers. f

Typical and illustrative embodiments of the invention are shown in the accompanying drawings in which;

Fig. 1 is a View, partly in side elevation and partly in vertical section, showing one form of my improved support, this view being taken as indicated byline i-l onFig. 2;

Fig. 2 is a vertical section taken as indicated by line 2 2 on Fig. l, both these figures showing Fig. 4 is an enlarged fragmentary section of certain portions shown in Fig. 2;

Fig. 5 is a horizontal section on line 5 5 of Fig. 4;

Fig. 6 is a horizontal section on line `6 6 of Fig. 4;

Fig. 7 is a fragmentary plan section showing the essential parts of the coupler and lock in their closed positions; l.

Fig. 8 is a similar view showing the parts in open position Fig. 9 is a longitudinal vertical section taken as indicated by line 8-9 on Fig. 8; but showing the parts in the position which is indicated by dotted lines in Fig. 8; y

Fig. 10 is a fragmentary view in side elevation and vertical longitudinal section showing a modi'- ed form of support, in itsupper or inoperative position;

Fig. 11 is a similar view showing the support lowered and in its operative supporting position;

Fig. 12 is a fragmentary section of certain parts shown in Figs'. 10 and 11 showing an intermediate position;

Fig. 13 is a fragmentary front elevation of the parts shown in Fig. 11;

Fig. 14 is a fragmentaryside elevation of certain parts shown in Fig.13, taken in the aspect indicated by the line l4-I4 on Fig. 13;

Fig. 15 is a similar View showing a `modification; and

Fig. 16 is a detail section taken on lineV lli-I6 of Fig. 15.

In the drawings a portion of the 4trailerframe is indicated at l0, the portions illustrated in Figs. 2 and 3 being one ofthe longitudinal side members of the frame. It will be understood that the supporting unit shown in these gures is preferably used in pairs, one at each side of the forward portion of the trailer; but as the units are duplicates it is necessary only to illustrate and describe one unit.

As typically illustrated in the drawings the supporting unit includes an upper hollow body member Il which is preferably made as a steel casting of such conguration as to be easily mounted, at l2, onthe trailer frame, and such as to provide accommodation for the other parts and `mechanism of the supporting unit. A cover plate 9 affords access to the interior mechanism. This body member Il extends downwardly yfrom the frame and its lower end portion I3 is of .circular tubular cross-section to take the vertically sliding tubular leg I4. Body portion I3 .has a groove or splineway I to accommodate a spline IB on the leg, to prevent rotation of the leg about its vertical axis. And the lower body portion I3 also is provided with a series of downwardly facing shoulders or teeth I'I in the form of downwardly facing ratchet teeth.

The lower end of tubular leg I4 is provided with a box 20, attached to the leg preferably by welding, The box is split as shown at 2l in Fig..13

and has one or more contraction.bolts,22 so, that the box may be constricted more or lessM tightly about the stub shaft 23 which. carriesa-t its-.op-v

posite ends two ground wheelsorrroll'ers 24'. Bore` 25 of box 29 is ared outwardlyL from the-.centerat both top and bottom as indicated in dotted lines at 25a. in Fig. 1 and as shown in full lines in Fig. 2. These ares are-onlypresentin the,

.integrally with or rigidwith respect to tubular leg I4, is adapted to press upwardly against the lower end face of pawl 48 when the weight of the trailer is being supported by the legs. This 'condition is shown in Fig. 2. In that condition shoulder 56 isv pressing upwardly against the lower' end surface of the pawl and the upwardly facing4 shoulder 53 of the pawl is pressing upwardly against one of the fixed downwardly facingratchetA shoulders I1a; and by that means the weight of the trailer is supported upon the legs. And, in that position of the parts, leg I4 and its lug 5I' are raised, with relation to the pawl, slightly above the relative position shown in Fig.

' 4, the clearance in lug bore 5,0. allowing that.

to thev other` supporting unit. An operatingshaft 32, preferably tubular, likewise extends across the width ofthe trailer between the two units, being journalledtherein at,33. At each end andwithin each. unit body the operating shaft carries a crank arm 34. Mounted in any convenient' position on shaft 32A there is an operating arm 35 which serves as the, arm through which the shaft 32 is oscillated from any suitable operating mechanism or motor. 'The vmotor which is here typically shown. is in the form of a Vacuum actuated diaphragm 35 having a rod'31 connected to operating arm 35. The arrangement is such that application of vacuum to the lefthand side of diaphragm 3E. willcause rotation of arm 35 and shaft 32 in a counter-clockwise direction in Fig. 1 and will lift supporting leg I4 through the mediumv of mechanism which is to be explained'. Upon relief of the. vacuumthe leg may` drop of its own weight, anda diaphragm spring 38 may aid movement of the parts in that direction. 'Relief of the vacuum is usually effectedby breaking-the vacuum line, which leads from the tractor'to the trailer, preparatory to uncoupling.

Operating shaft 32 carriesV anotherarm 3 9 to whicha control rod 4B is pivotally connected. This rod goes to and operates and controls the lock.controllingmechanism of the coupler, as will be hereinafter described. Arm 3 9 bears certain angular relations to the operating crank 34 and rod; 40, as will be hereinafter described; so as to effect certain cooperative controlfunctions. Operating arm 35 on shaftV 32may, incertain installations, be one and the saine with control arm 3S. v

A link. or connecting rod (l5 depends from a pin 46 at thel endV of operating crank I34, and the lower end; of connecting; rod v connects to a stud 4'@ which projects from the back side ofa pawl 48. Pawl 48 is hung at itsvupper end on pin 49, the latter being rigidly: mounted in the pawl and carried loosely in an opening 50 in a lug 5I whichis formed as a part of' or welded tothe upper end of tubular leg I4. Lug opening 50 allows. pin 49. a limited freevertical movement. The

lower end ofpawl 43 carries a head 52 adapted to' flt the ratchet formation of teeth I-"l and' having i The uppermost raised position. of the leg is shown in Fig. I3, where the leg has raised to its upper limit with box'2li in contact with the lower end of body IfI. In this position operating shaft 32 and its attached operating crank 34 and arms 3,5 and 39 are in positions rotatedcounterclockwise from the positions shown in Fig. 1 by an angle of about In this uppermost position leg I4 and allv its connected parts are suspended from operating crank 34 through the connecting rod 45. The support ofthe leg from link 45 is through pawl 48. Stud 4'I` onthe back of the pawl being offset from a vertical line through pivot 49, the pawl is swung into the angular position shown in Fig. 3, against the action of pawl spring III.v Stud 41 strikes a lug 6I' on the innerfaceY ofY tubular legv I4 to limit this angular position. In this position the pawl head 52 is withdrawn inwardly through opening 55 so that th'epawl' head does not project outwardly beyond the outer periphery of the'tubular leg. With the pawl supported'in the position illustrated, the tubular leg I4, and'ground wheels 24, are then supported from pawlpivot 49 through the lug 5I Whichloosely'engages that pivot pin. The action of loweringthe supporting leg is essentially that of' merelyl releasing the supporting pressure on diaphragm 36 and allowing the leg to drop. The main impelling force in lowering the leg is the kweighto the leg and its connected parts. As

and in some instances the leg will drop to its lower`v stopped limit without ground wheels 24 reaching contact with the ground. The limit to downward movement of 'the leg is formed by a pair of stop lugs 10 which project from the upper end of pawl 48` and overhang the outer periphery of tubular leg I4 in such a manner as toV strike an upwardly facing shoulder 1I which is formed on body I I just above theratchet teeth I1. With lugs 13 resting on shoulder 1I, pawl head 52 is at an elevation where its upper shoulder face 53 is just slightly below the lowermost ratchet shoulder Ila; and the engagement f lugs taken on ground wheels 24 and on the leg, the leg shoulder 55 comes up against the lower-end of pawl 48, and the upper shoulder face 53 of pawl head 52 moves up against the ratchet shoulder IIa, to support the weight. As the leg I4 moves up the short distance with relation to pawl 48, the loose play in the bore at 50 around pawl pivot pin 49 allows the necessary short relative movement without placing any of the weight strain on pivot pin 49.

In other circumstances of operation the ground wheels will engage the ground or roadway before the leg has dropped to its lowermost position and before the pawl has reached a position to engage with the lowermost ratchet shoulder. The series of ratchet'shoulders is provided for establishing the weight supporting connectionA between the supporting leg and body member II at various elevations, so as to make the support completely usually encountered.

Assuming a ground condition in which the ground wheels engage the surface when pawl 48 has dropped to a position where its shoulder face 53 will then just enter under uppermost ratchet shoulder I'Ia, the operation is as follows. the parts in the last dened position, and with the leg supported upon the ground we will assume that the weight of leg I4 and its attached parts has dragged the connecting rod 45 and its attached parts downwardly. This will usually be the case as spring 38 is usually light and, as will be seen, the movement of the parts also includes movement of connecting rod 40 and its attached parts, which constitutes a drag upon the movement. Consequently pawl 48 will reach' a position opposite the uppermost ratchet shoulder (with pawl shoulder 53 at a level just below uppermost ratchet shoulder IIa) in a position, with relation to the leg, likeA that shown in Fig. 3; and the parts 39, 4D, etc., will not have been impelled by spring 38 into movement ahead of the downward movement of the pawl. even if the connecting rod 45 be a simple open link.

Having reached the latter described position. the pawl head 52 is immediately moved toward the left and under uppermost ratchet shoulder I 1a. This movement is caused by the constant pressure of spring 60, if by no other force. It may however be at least partially caused by the action of diaphragm spring 38 which may also tend to continue rotation of operating shaft 32 and op- With erating crank 34 in a right-handed direction. If

link which constitutes the connecting rod is then provided with stop pins 45a (or what amounts to the same thing, if connecting rod 45 is made with solid bearings at each end instead of in the form of an open link) then the pressure of spring 38 will also be transmitted to pawl lug 4'I to throw the lower end of the pawl toward the left and under the uppermost ratchet shoulder I'Ia.

In passing, it may be remarked that the stop pins 45a are in practice not found to be necessary as diaphragm spring is not usually heavy enough to itself move the parts in such manner as to lower link 45 below the position to which the link and the parts connected to it have been moved by the weight of the leg and by the pawl spring 60. Thus, in practice, link 45 may be a simple open suspension link. The head 41a of stud 41 extends out laterally beyond the diameter of the stud only in a horizontal direction. The link can be easily assembled with the stud by turning the link crosswise of the pawl, and the notches I4a in the upper end of legv I4 facilitate this assembly operation. y l

In any case, to enter the pawl under the uppermost ratchet shoulder, the supporting leg and the pawl will have-moved down vertically to the specied elevation, and then, by a swinging movement of the pawl accompanied by further downward movement of 1ink`45`and further rotation of operating shaft 32 and control arm 39, the leg I4 will be locked in position relative to body member II. i And it is that last mentioned locking movement which is utilized for unlocking or releasing the coupler in a, manner now to be described. In the illustrative design shown in the drawings, the pivotal connectionv 39a, between. control arm 39 and control rod 40, has just reached a point in its movement which is designated diagrammatically by the mark at 39h on the drawings, when the parts have gone through theirV final movement of locking the leg. In this position of the parts control rod 40 has just reached the position where its operated lock controlling parts have just unlocked or released the coupler, And in that last mentioned position of the parts, the controlling rod 40 and its operated parts have moved into the coupler releasing position during the last mentioned motion of pawl 48 into locking engagement with the ratchet shoulder I'Ia. Y

A typical form of coupler lock and controlling mechanism is shown in Figs. 7, 8 and 9. The forward part of the trailer frame is shown fragmentarily at IIJa. This forward part of the frame includes a framing plate 88 upon which certain parts of the coupler and locking mechanism are mounted and which also has a longitudinal slot 8I through which the'tractor king-pin 82 may enter by relative rearward motion. The coupler member 83 is in the form of a hook pivoted at 84 to swing between the positions shownin Figs. 7 and 8. The rearwardly moving king-pin strikes a shoulder 85 on the coupler to throw it to the closed position shown in Fig. '7. In movingl to that closed position the beveled end 86 of the coupler member strikes upon the nose face 81 of spring-pressed latch holt 88 to push the latch bolt back so that the coupler membernally. reaches the position shown in Fig. 7 where it is locked by the spring-pressed latch bolt.

A latch operating lever has an arm 90 which lies in the position shown in full lines' in Figs. l and 8 when the latch bolt is fully extended. To release the coupler the latch bolt `is retracted far enough that its beveled nose face 9| will be engaged by nose 92 of coupler member 83 as the latter swings toward the open position of Fig. 8, so that the latch bolt will be pushed further back as the coupler swings open. In the arrangement as here shown the latch bolt is cocked in its partially withdrawn position, with lever 90 in the position shown in dotted lines in Fig. 8, by a manual setting which is accomplished by pulling outwardly on control bar 93 and hooking a hook 94 upwardly over a lug 95 on the frame. With the parts in such position (shown in Fig. 9) the latch bolt 88 is withdrawn far enough that coupler nose 92 then pushes the latch further back as the coupler opens. The accompanying slight forward movement of bar 93 and hook 94 releases the hook from lug 95 and the hook dropsY away from the lug so that when coupler nose 92 has passed the latch bolt the latch bolt then springs back to its fully projected position as shown in Fig. 8, ready to latch and lock the coupler immediately upon reinsertion of the Spring 99. In the position shown in Fig. 7 the locking nose of locking-pin 98 is held back against the action of spring 99, by coupler arm 96,. and in this position nose |00 just clears a longitudinal slidable control bar |0|V vwhich is attached to the forward end ofand moves with the controlling rod 40. Control bar |0| has an aperture |92 of a size to take the locking pin 98 when the aperture comes into register with-thelockingpin. Aperture |02 is a little larger than the locking pin, for reasons which will hereinafter appear, but the relation of aperture |02 to control rod is such that when pivot pin39a in Fig. l has just reached the previously defined position indicated by 39h, then the forward edge of' aperture |02 (the right hand edge in Fig. 7) has just moved forward far enough (toward the right in Fig. 7) that locking pin 98 can pass 'through the aperture to lock control bar |0| in position and to release coupler arm 96 to swing free of lug 91. Such condition of the parts is shown in Fig. 8, the release of arm 96 having allowed the coupler to open. However, in the par- I ticular locking mechanism which is here being described, the coupler cannot open until latch 8B cocked, and until that occurs the coupler arm 96. holds lock pin 98` from entering aperttt-re |02.

VWhen control bar |0| moves forwardly to the last described position a control rod |-04 moves forwardly with it. This rod |04 has a head |05 on its forward end, which lies just forward of a lug |06 on the outer end of latch lever 90 and, in the position of the parts shown in Fig. 7, prevents latch lever 90 from being moved forward to cock the latch. With the parts in the position which has been described-with locking aperture |02 just forward far enough to allow lock pin 98 to enter-rod head |05 is forward far enough to allow the latch to be manually cocked as before explained and to allow' the subsequent short forward movement of latch lever 90 which accompanies the opening of the coupler: In that position of the parts, then when `king-pin 82 iswithdrawn by relative forward mechanism is such that the coupler is only released or unlocked when control bar |0| has reached the specified position, which it only reaches when the pawl 48 has reached a position at the level of the uppermost ratchet shoulder lla and then has nally moved in under that ratchet shoulder. The coupler is thus finally released or unlocked by virtue of the nal movement which takes place in connection with the final locking of the leg in its lowered position. The action of aperture |02 registering with lock pin 98. is an action which (disregarding the manual coupler release) directly releases or unlocks the coupler. The action of control rod |04 is one which releases the coupler lock to be manuallyv unlocked; and'this action, as -well as the direct coupler release, does not take place until the locking pawl 46 goes through its final locking movement. In the appended claims we use the term release, as applied to the coupler or draftlock, to mean either its complete unlocking, or its freeing to be subsequently unlocked.

Under other conditions of leg lowering, Where the ground wheels do not strike the road surface until the leg has been lowered to lower levels. the coupler is released or unlocked by virtue of l f the. movement of the leg below the level at which pawll head 52 reaches the level of the uppermost ratchet shoulder Ha. Whenever the leg moves down far enough to carry the pawl below that level, then the. movement of the pawl, beyond the movement which is required to carry the pawl to that level, is a movement which at least puts the pawlpotentially in acondition where it must lock the leg immediately upon upward movement of the leg with reference to body member |.v

For instance, it maybe assumed that the leg has dropped to a position where the nose of pawl head 52 rides on a nose of one of the ratchet shoulders. In any such position, as. soon as the leg is pressed relatively upwardly by the weight of the trailer coming upon it, then pawl head .52 will immediately be moved upwardly and outwardly into engagement with the ratchet shoulder lla which is next above. The movement of the pawl below the level of uppermost ratchet shoulder Ila may therefore be viewed as the potential locking movement of the pawl if not the actua-l locking movement.

In any such potential locking position of the pawl,A it may have travelled downwardly some distance'below the level of the uppermost ratchet shoulder lla. Arm 39 has correspondingly travelledv to and past the point indicated by the numeral 39h, and control bar |0| has Correspondingly been moved to and somewhat past the initial registering position which has 'been previously described. The relative position of arm 39 on shaft 3.2 is such that, during the. travel of arm 39 from the point. 39h to its position of ultimate travel with the leg furthest down (shown in Fig. 1) the arm 39 travels through a. short arc whichis close to a dead center position. In Fig. 1 thev dot-dash line labeled C represents the effective dead center line for the connecting control rod 40. Travel of arm 39 from point, 39h tothe position shown in Fig. 1 moves control rod 40 and control bar |0| only a slight distance beyond the position assumed by those parts when arm 39 is in the rst registration position represented by point 3.9i). Locking aperture |02 is. suiliciently elongated with respect to the size of locking pin 98, to keep the aperture in register with locking pin 98 at, all times after arm 39 has passed the point 39h.

Figs. 10 to 16 illustrate a modified form. of drop leg support which cooperates with the coupler and the, coupler locking mechanism in the same manner as before described. In these figures `the upper or body portion of the support is in similar to the box previously described for carrying the ground wheels, 206.

The operating shaft 201, with a crank 208, operating arm 209 and control arm 210, are all generally similar to the corresponding parts previously described, and the operating shaft and its connected parts are operated by a vacuum diaphragm 2|| which is similar in structure and operation to that previously described. An aperture lug |99 welded on Ibody tube 200 and clamped in the clamp bracket makes `provision for alining the body tube and for vertical adjustment. And the bearings of shaft 201 are likewise vertically adjustable by the arrangements shown at |98 in Figs. 13 and 15.

A connecting rod'or link 2|2 depends from operating crank 208 and moves between the upper position shown in Fig. 10 and the lower position shown in Figs. 11 and 12. Connecting rod 2 I2 in this form of device is double, and its lower end straddles a transverse pin 2|3 which is set in the .upper part of tubular leg 204. Just below the transverse pin the lower end of link 212 carries pivot pin 2|4 on which the pawl 2l5 is dependingly mounted, Pawl 2|5 is carried between the two spaced parts of link 2|2 so that the upper end of the pawl pulls up against cross-pin 2|3 when links 2|2 are raised, and thus causes the whole drop leg to be raised whenever the parts are moved up to the position shown in Fig, 10. At its lower end pawl 2 I5 has a head 2|6 with a curved lower surface which rides on an inclined guide 2|1 which is inserted in and carried by the tubular drop leg, The arrangement of the parts is such that the pawl assumes the position shown in Fig. 10 when the parts are raised, but is capable of assuming the position shown in Fig. 11 when the parts are lowered.

The tubular leg has a pawl projection opening 2|8 just above the transverse guide 2|1. In the lowermost dropped position of the leg, shown in Fig. 12, opening 2|8 is just below the lower end 219 of tubular body member 200. In that position of the parts further downward move- I ment of link 2|2 has been stopped by crank arm 208 coming into contact with the inner surface of body tube member 200, as shown in Fig. 11, and the tubular drop leg is hanging on links 2|2 with the parts in the position shown in Fig. l2. In that position diaphragm spring 220 exerts sufficient force tohold crank arm 208 from being rotated in a counterclockwlise direction by an upward push on link 2|2. Then, iwhen the weight of the trailer is lowered onto the drop leg, leg 204 is pushed up into body tube 200. Inclined guide 2|1, by that upward movement, swings the lower Aend of pawl 2|5 outwardly toward the right from the position shown in Fig. l2 to the position shown in Fig. 11. In the latter position pawl head ZIB rests upon guide 2I1 and is projected under the lower edge 2| 9 of body tube 200. Drop leg 204 is thus locked in its lowermost position in which it supports the weight of the trailer.

is therefore either its potential locking movementl or its actual locking movement, depending on whether the leg has dropped clear down (Fig. l2)

and then moved back up again, or has struck the ground in about the position of Fig. 11 and before reaching that of Fig, l2. In the latter case, with the leg in the position of Fig. 12, the last part of the downward movement of links 2|2, impelled by diaphragm spring 22|), acts dil rectly to force 'the pawl on downwardly and outwardly to the locking position of Fig. ll. In either mode of operation it is that last downward movement of the locking pawl which throws control arm 2 0 and its connected control rod 24B to the position where the coupler is unlocked or released for unlocking in the manner before described. i

Figs. 13 and 14 show a yielding detent device which operates to hold the operating shaft 201, and crank 208, in the position of Figs. 11 and 13. An arm 225 is mounted on shaft 201 and carries a spring pressed detent ball 226 which engages a depression in plate 221. The detent action is sucient to hold the parts in the position of Figs. 11 and 12' as the leg 204 is moved up by ground contact, thereby insuring that pawl 2|5 will be forced out rather than be forced up.

With the slight modication shown in Figs. l5 and 16, this device may also provide for hand operation of the support. In those figures arm 225 is extended to form an operating handle 228. Two depressions or bores 229 and 230 are formed in plate 221, the former to hold the parts in the position of Fig. 11, the latterto hold them in the position of Fig. 10 withthe leg elevated. And instead of using a. spring pressed ldetent ball, this modification uses la manually retractible spring pressed plunger 23 l We claim:

1. In a tractor and semi-trailer combination in y which the tractor and trailer are provided with interengaging draft elements including a releasable draft lock on oneA vehicle adapted to lockingly engage the draft element of the other vehicle, and in which the trailer is provided with a support movable between supporting and nonsupporting positions; the improvement which is characterized by the trailer support carrying a locking element for movement therewith and for 'limited locking movement with relation thereto to lock the support in supporting position, the support being movable between supporting and non-supporting positions by movement applied to the locking element, and interconnective means between the locking element and the draft lock operating to release the draft lock upon locking movement of the support locking element.

2. In a tractor and semi-trailer combination in which the tractor and trailer are provided with interengaging draft elements including a releasable draft lock on one vehicle adapted to locking'- ly engage the draft element of the other vehicle, and in which the trailer is provided with a support movable between supporting and non-supporting positions; the improvement which is characterized by the trailer support carrying a locking element for movement therewith and for limited locking movement with relation thereto to lock the support in supporting position, the support being movable between supporting and nonsupporting positions by movement applied to the locking element, interconnective means between the locking element and the draft lock operating to release the draft lock upon locking movement of the supportl locking element, and support moving mechanism connected to the locking element and adapted by initial movement to move the support to supporting position and by final movement t give locking movement to the support lock.

3. In a tractor and semi-trailer combination in which the tractor and trailer are provided with interengaging draft elements including a releasable draft lock on one vehicle adapted to lockingly engage the draft element of the other vehicle, and in which the trailer is provided with a support movable betweensupporting andvnon supporting positions; the improvement which is characterized by the trailer support having a'lock operative by locking movement to lock the support in supporting position, support moving mechanism connected to the locking elementA and adapted by initial movement to. cause. movement of the support to supportingpositionand bvfinal movement to give` locking movement toi thel suo port. lock. and interccnnective; means. between the supportmcving mechanism and the draftlock operating to release. the draft. lock uponnnal support looking; movement of. the. moving mechamsm.

4.. In a traetorandsemietrailer combination. in which the tractor and .trailer are. provided; with interengagine. draft. elements.; includinga .releasable draftloclr on.- onei vehicle4 adapted to lockingly, engager the draftrelement of the other vehicle, and in which the trailer; is` provided: with a. support movablebetween supportingandnon.- supportingA Positions; the; improvexnent;` which is characterizedby the trailer supporthaving a lock operative by locking movement to lock the sup.- pcrt supporting. position.. support moving` mechanism connected. tothe locking element and adapted by initial movement toy causamovement of the support to supporting position and,by inal 'movementto givelocking movement to the support lock, and interconnective means between the support moving mechani.smy and thedreft .luck ccntrcllingthe release ot the draftloch 5. In a tractor and semntrailer combination in which ,thtractor and trailer arel providedwth interengaging. draftv elements including a releasable draft locken, ene vehicle. adapted. to. lock-Y irlgly engage.. the. draft element of; the other vehicle, andin which. thetrailer is, provided with a supportl movable between, supportingl and` non- Supporting. ncsitions,;.tbe improvement which is characterized by the support. being in4 the-formv oi a. movable legl which may. be raised and. low.- ered, a lock element carried by, the movable leg and` movable. with` relation thereto, leg moving mechanism. connected. to. the lock element, and. interecnnective means between the; leg-meting. mechanism. and the draft. lock controlling the release of the draft lock.

6.. In a tractor. and semi-trailer combination in which thetractor and trailer are provided with interengaging draft elements including areleas.- able draft lock` on one vehicle adaptedto. l0ck. ingly engage the draft element of the. other vehicle, and in whichv the trailer isprovided with. a support movable between supportngand nonsupporting positions; thelirnprovement which 'is characterized by the support including a substantiallyvertical'` guide and a movable legjl guided thereby, a pivotedl locking pawl carriedby the movable legV andadapted to swing transversely of the leg movementto lockinglyl engage the guide',` legwmov-ingl mechanism-1'connected to a point-on the locking pawl whichhas a vertical component of movementas the pawlswings and interconnecti-ve means between thelegfmoving ymechari-ism' and-the dratt` loclr-A controlling-the release-ofthedraft locke.

.adapted to be secured tothe trailer frame `and having a downwardly facing locking shoulder, a

v movable leg slidable on the guide member in a vertical direction, a locking pawl loosely mounted on the leg to move both horizontally and vertically with reference thereto and adapted by horizontal movement to project under the locking shoulder of the guide, an upwardly facing shoulder on the leg adapted to bear upwardly on the pawl, and leg moving and suspending mechanism connected to the locking pawl.

8. Support as specified in claim 7, and in which the upwardly facing shoulder on the leg has an inclined face which forces tlie'pawl into projected position when the ieg is moved upwardly with reference to the pawl.

9. Support for a semi-trailer or the like; cornprising the combination of a leg guiding member adapted to be secured to the trailer frame` and having a downwardly facing locking shoulder, a movable leg slidable on the guide member in a vertical direction, a locking pawl mounted on the leg to move both horizontally and vertically with reference thereto and adapted by horizontal movement to project under the locking shoulder of the guide, the pawl mounting allowing the pawl a limited loose vertical movement with reference to the leg, an upwardly facing shoulder on the leg adapted to contact with and bear upwardly on the pawl when the leg moves upwardly with reference to the pawl through a distance lessthan the relative vertical looseness between the leg and pawl, and leg moving and suspending mechanism connected to the pawl.

10. Support for a semi-trailer or thelike; comprising the combination of. a leg guiding member adapted to be secured to the trailer frame. and having a downwardly facing locking shoulder, a movable leg slidable on. the guide member in a. vertical direction, a locking pawl dependingly piv oted on the leg and having a head*v at its lower endV adapted to be` projected horizontally under the locking shoulder'of theguide,4 and legmoving and suspendingy mechanismA connected to `a point on the pawl which is offset horizontallyfrom a vertical linethrough the pawl pivot, so that the weight: of the leg tends to retract the projectible head of the pawl, the pawl beinggloosely pivoted to the leg, and the legv having an upwardly'facing shoulder adapted to 4bear on the pawl head.

l1. Support fory semi-trailersor the like, com.- prising the combination of a tubular body member adapted to be secured to atrailer frameand to form a vertically extending4 tubularv guide, a series of vertically spaced downwardly 'facing locking shoulders on the body member," a tubular leg vertically slidable in the4 body memberra'pawl pivotally mounted at its upper end on the leggand depending. within thexleg, the leg wall having an opening and the pawl having an outwardly projecting head at its lower endladapted to beprojected through the opening and under anyone of the locking shoulders on thebody, and means urging the pawl headV outwardly.

' 12.v Support forsemi-trailers or'the like,A comprising the combination cfa tubular body'member adapted to be secured to a trailer' frame and to form a vertically extending tubular guide,- a series of verticallyI spaced downwardly facing locking shoulders on--the body member, atubular leg vertically slida-blefin thetbody member; apawl pivotally-mounted at its upper end onthe leg and depending within the leg; the leg' wall-having an opening and the pawl having an outwardly projecting head at its lower end adapted to be projected through the opening and under any one of the locking shoulders on the body, and a spring urging the pawl head outwardly.

13. Support for semi-trailers or the like, comprising the combination of a tubular body member adapted to be secured to a trailer frame and to form a vertically extending tubular guide, a series of vertically spaced downwardly facing locking shoulders on the body member, a tubular leg vertically slidable in the body member, a pawl pivotally mounted at its upper end on the leg and depending within the leg, the leg wall having an opening and the pawl having an outwardly projecting head at its lower end adapted to be projected through the opening and under any one of the locking shoulders on the body, a connection lug extending from the inner face of the pawl and lying inside a vertical line passing through the inclined pawl-engaging shoulder extending across the interior of the tubular leg below the opening, a leg moving link depending into the leg, a pawl mounted on the lower end of the link and having a head adapted to contact the inclined` shoulder and t0 be projected through the opening, and a stop` secured to the leg to limit upward movement of the pawl and link with reference to the leg. f

l5. Support for a semi-trailer or the like; comprising the combination of a leg guiding member adapted to be secured to the trailer frame and having a downwardly facing locking shoulder, a movable leg slidable on theguide member in a vertical direction, a locking pawl mounted on the leg to have a limited movement with reference thereto both horizontally and vertically and adapted by horizontal movement to project under the locking shoulder on the guide, said relative pawl movement being so constrained that its relative horizontal and vertical movements are interdependent, a draft coupler lock, and connection between the locking pawl and the coupler lock whereby the relative Vertical movement of pawl both upwardly and downwardly is transmitted positively to the coupler lock.

ROBERT M. BARNHART. JOHN C. BENNETT. PERCIVAL M. HEINMILLER. 

